Connect C++ variable to 3d cockpit via modeldef.xml

[Mauro]

Hi to all,

I'm working on a 3d cockpit, following this "standard" procedure:

1. create an XML variable in modeldef.xml file, using simulator token variables. Example:
   

       <PartInfo>
         <Name>needle_g_force</Name>
         <AnimLength>85</AnimLength>
         <Animation>
           <Parameter>
             <Code>(A:G FORCE, GForce) 10 * 50 + 0 max 170 min 2 /</Code>
           </Parameter>
         </Animation>
         <MouseRect>
           <Cursor>Hand</Cursor>
           <TooltipText>GFORCE %((A:G FORCE, GForce))%!2.1f! g</TooltipText>
         </MouseRect>
       </PartInfo>

2. in 3dsmax, I link an animated object (es, a needle) with that variable via FSTools
3. the 3d object is exported as .x file, with an associated .xanim file containing the animation description
4. via XToMdl.exe tool, I convert the .x file in an .mdl file, to be used as internal model for my airplane

This approach works fine, but has several drawbacks (postfix notation, difficult debugging, etc).

What I would like to do is create a custom variable, to be used in substitution of default variables inside modeldef.xml. Continuing the previous example, I would create a custom variable MY_G_FORCE:

//C++
bool GForceGaugeCallback::GetPropertyValue (SINT32 id, FLOAT64* pValue)
{
   ...
   FLOAT64 gforce = aircraft_varget(get_aircraft_var_enum("G FORCE"), get_units_enum("GForce"), 0);
   gforce = 10*gforce + 50;
   *pValue = gforce < 0  ?  0 : (gforce > 170) ? 170 : gforce;
   *pValue /= 2;
...
}

and then refer it in XML:

<!--modeldef.xml-->
  <PartInfo>
   <Name>needle_g_force</Name>
   <AnimLength>85</AnimLength>
   <Animation>
       <Parameter>
         <Code>(L:MY_G_FORCE, GForce)</Code>
       </Parameter>
   </Animation>
    ...
  </PartInfo>

I worked with Cabin Comfort example, and while it works fine as 2D gauge, I was unable to use its variables in modeldef.xml for 3D gauges: I tried to connect to its variable BankAngle, using all of the following:

1. <Code>(C:CABIN:BankAngle, degrees)</Code>
   
2. <Code>(C:BankAngle, degrees)</Code>
   
3. <Code>(C:CABIN:BankAngle)</Code>
   
4. <Code>(L:CABIN:BankAngle, degrees)</Code>
   
5. <Code>(L:BankAngle, degrees)</Code>

but no luck. It was always evaluated to zero.

Then I went in debug mode in C++, and I saw that the function bool CABINGaugeCallback :: GetPropertyValue (SINT32 id, FLOAT64* pValue) is called only for updating the 2D gauge, and not for 3D gauge.

As you can see in Cabin Comfort example, the variable is referred in this section of CabinComfort.xml:

        <Element id="Element">
            <FloatPosition>120.000,55.000</FloatPosition>
            <GaugeText id="GaugeText">
                <Bold>True</Bold>
                <FontColor>yellow</FontColor>
                <FontHeight>11</FontHeight>
                <GaugeString>%((C:CABIN:BankAngle))%!2.2f!</GaugeString>
                <HorizontalAlign>RIGHT</HorizontalAlign>
                <Size>80,13</Size>
                <Transparent>True</Transparent>
            </GaugeText>
        </Element>

Does anybody have any suggestion? I'm really interested in porting all of the logic in C++ as I'm a developer, and I feel much more comfortable with it than with XML.

Thanks very much in advance!
Mauro

 

[JB3DG]

http://www.fsdeveloper.com/wiki/index.php?title=C:_XML_Variables_in_C_Gauges

You don't need to do the check_named_variable part though. You can get the id value when you do the register_named_variable as it returns the ID value and you only need to do that once. I should also note, rather than using the unit identifier "GForce" for your L var in the modeldef, use "number".

 

[taguilo]

What I would like to do is create a custom variable, to be used in substitution of default variables inside modeldef.xml

As you have already noticed, custom (C: ) vars are not supported in modeldef.xml scripts.

And the Cabin Comfort method is not a suitable example in this case.

You only need to work with LVars from inside your C++ gauge, like described in the Wiki's reference.
Also there is no problem to keep their default units instead of number, they are supported in XML scripts (modeldef included).

Tom

 

[Mauro]

Thanks for all responses. I have an update. I kept on working on Cabin Comfort, following these steps:

1. in modeldef I connected the animation to the variable (L:BankAngle, number)
2. in FSX, I opened the Cabin Comfort panel, and I saw the 3d part following correctly the variable
3. unfortunately, as I removed the Cabin Comfort panel, the 3d part stopped moving

Using C++ debugger, I saw that the update functions are called only if the Cabin Comfort panel is opened.

So, the problem is: how can I trigger a callback from modeldef to C++, in order to update the variable?

Thanks,
Mauro

 

[taguilo]

So, the problem is: how can I trigger a callback from modeldef to C++, in order to update the variable?

You can't. Did you read my former post?

The Cabin Comfort method is for building generic .dll modules that must be declared in DLL.XML file. Not suitable for using them as gauges defined in panel.cfg.

Tom

 

[Mauro]

Hi Tom,

I understand Cabin Comfort is not the perfect example for my needs but - as far as I know - it's the only one provided by FSX, except for the SDK example, which is even worst.

I took a look at the wiki http://www.fsdeveloper.com/wiki/index.php?title=C:_XML_Variables_in_C_Gauges, as suggested by Naruto-kun, but even there it's not clear in which method I should put the updating code. Have you any hint?

Thank you very very much, and sorry for trivial questions
Mauro

 

[JB3DG]

Try this:

http://www.fsdeveloper.com/forum/resources/blank-invisible-systems-gauge-template.164/

Map it to a hidden polygon using a VCockpit entry in your panel cfg.